Tool for Automation and Testing Expect Tool for Automation and Testing

Expect - Introduction Unix automation and testing tool Written by Don Libes Primarily designed as an extension to the Tcl scripting language Useable in interactive applications such as telnet, ftp, passwd, fsck, rlogin, tip, ssh, and others.

Expect – TCL* Basics Everything is a command No Fixed Parser Case-Sensitive Explicit Expression Evaluation set a 5  a = 5 set b a+2  b = a+2 set c [expr $a+2]  c = 7 (Note: $ for variable substitution) Simple variables are strings of arbitrary length Real & Int  cast to real Non-numeric string and real/int  cast to string Built in Lists Standard flow control structures (while, if, etc.) String manipulation with Regular Expressions Procedures – arguments can be passed by value or reference *Tool Command Language

Expect – The Programming Language Extension of TCL, so the syntax is TCL syntax Basic command set expect send spawn Interact Regular Expression pattern matching “Glue” to combine separate executables

Expect – Pros / Cons Pros Cons Built on existing system tools, so learning curve is small. Extensive support from corporate entities* *Silicon Graphics, IBM, HP, Sun, Xerox, Amdahl, Tektronix, AT&T, ComputerVision and the World Bank Numerous ports to other programming languages (Perl, Python, java, etc.) Cons Only useful for command line scripting Cryptic syntax for those unfamiliar with TCL (When do I use a $ again?) Generally machine dependent tools are run with Expect, so porting scripts cross-platform is not easily supported.

Expect – “Hello World!” Start Expect with “expect” or write the script to a file and run > expect filename send “Hello World!\n” expect “Hi\n” Putting it together Expect “Hi\n” { send “Hi World!\n” }

Expect – More Advanced expect "hi\n" { send "Hi World!\n" } \ "hello\n" {send "Hello World!\n" } \ "bye\n" {send "Bye World!\n" }

Expect - Automation spawn ftp $argv expect "Name" { send "anonymous\r" } \ "name" { send "anonymous\r" } expect "assword:" send "nobody@nobody.com\r" interact

Expect - Others Brute Force security Beer Chess Weather Rogue Hunt

Expect - GnuChess # start things rolling spawn gnuchess set id1 $spawn_id expect "White \\(1\\) :" send "random\r" send "depth 6\r" send "go\r" # read_first_move expect -re "My move is : (.*)\n" set id2 $spawn_id send "depth 5\r" send $expect_out(1,string) while {1} { expect { -i $id2 -re "is : (.*)\n" { send -i $id1 $expect_out(1,string) } -i $id1 -re "is : (.*)\n" { send -i $id2 $expect_out(1,string)

Expect - Questions